Feedback diversity with every game update.
I believe Discord, reddit, twitter -all social spaces- gravitate towards hype and positivity (which is great!) over weighty criticism. There is pressure to not sound like a nitpick and avoid raising things that don't good look to say - even if they're valid.
Game balancing treads a thin line between appeasing public narratives and maintaining long term game health. Concerns about item inflation vs profitability would not come off positively to most people, for example. An anonymous channel would let players raise concerns without fear of being misread or seen as negative. It gives the community a safer way to surface issues that might otherwise go unspoken, and it gives the devs a clearer signal of potential problems early on.